Hydrocarbons, such as crude oil produced from underground reservoirs, often contain many compounds which are entrained within the crude oil. For example, an oil well will frequently produce large quantities of water, gas, carbon dioxide, solids and crude oil. Certain of these constituents are not only undesirable components of the oil, but frequently are quite difficult to separate from the oil because they have become emulsified with the oil during production.
This is undesirable since purchasers of crude oil stored in tanks may reject the oil if the bottom sediment and water concentration in the tanks exceed one or two percent. Accordingly, the hydrocarbon fluids are commonly treated to separate the oil from the impurities that are produced with the oil.
When emulsion is not a factor, portions of the impurities in a tank, such as water, paraffin and other impurities, may eventually settle to the bottom of the tank due to differences in the specific gravity of the impurities. If these impurities are allowed to accumulate and solidify, the storage tank can be very difficult to treat and clean.
To prevent the accumulation of impurities at the bottom of storage tanks and to de-emulsify crude oil emulsions with the addition of chemicals, a "rolling process" can be used to circulate the hydrocarbon fluids, thereby dispersing the paraffin evenly throughout the crude oil and causing the solids and water to become de-emulsified and to segregate at the tank bottom for removal. The crude oil is then ready for sale. However, the adding of chemicals or use of other techniques involved with the "rolling process" require the addition of expensive chemicals or expensive manual labor, or the expense of energy for heating.